A Justice may deem a statute to be unconstitutional only when, after careful analysis, the Justice determines that the statute clearly conflicts with the Constitution. A Justice may not deem a statute to be unconstitutional if the relevant constitutional provision, at the end of the analysis, has two or more plausible meanings and the statute is consistent with one of those plausible meanings. It’s not enough, in other words, that the statute is inconsistent with what the Justice regards as the best reading of the constitutional provision. If there remains a plausible alternative reading that can be reconciled with the statute, the Justice must apply the statute.

This concept might fairly be labeled a “presumption of constitutionality.” A statute, that is, is presumptively constitutional. That presumption may be rebutted, but only by showing that the statute clearly conflicts with the Constitution.

This principle has deep roots. Indeed, it inheres in the very foundation of what we call judicial review: the power or, perhaps better, the duty of federal courts to decline to apply statutes that violate the Constitution. In his justification of judicial review in Federalist 78, Alexander Hamilton explains that the Constitution is a “fundamental law” that, like any other law, judges must interpret in order to “ascertain its meaning.” In the event of what Hamilton calls an “irreconcilable variance” between the Constitution and an ordinary statute, judges need to apply the Constitution, the law of, as he puts it, “superior obligation and validity,” in preference to the statute. Chief Justice Marshall’s exposition of judicial review in Marbury v. Madison closely tracks Hamilton’s reasoning.

This is an important strand of originalism theory, associated with academic theorists such as John McGinnis and Richard Kay. It's not the same thing as pure judicial restraint -- all of these authors would accept courts finding laws unconstitutional in a wide range of areas. But it's a key counterpoint to the more fashionable "New Originalism," which posits that when originalism "runs out" -- that is, when originalism cannot provide a clear answer -- judges can supply outcomes through "construction." The Whelan/McGinnis/Kay thesis, in contrast, I understand to say that when originalism runs out, so does a judge's authority to find a law unconstitutional.